"Helmet fire" is an expression for a mental state characterized by unnaturally high stress

Stress (medicine)

Stress is a term in psychology and biology, borrowed from physics and engineering and first used in the biological context in the 1930s, which has in more recent decades become commonly used in popular parlance...

 and task-saturation and loss of situational awareness. The term originates in the military pilot

Aviator

An aviator is a person who flies an aircraft. The first recorded use of the term was in 1887, as a variation of 'aviation', from the Latin avis , coined in 1863 by G. de la Landelle in Aviation Ou Navigation Aérienne...

 community: military pilots are trained in high-performance aircraft and wear helmets to protect their cranium and muffle out engine and wind noise. A fire

Fire

Fire is the rapid oxidation of a material in the chemical process of combustion, releasing heat, light, and various reaction products. Slower oxidative processes like rusting or digestion are not included by this definition....

 aboard any aircraft is considered a serious emergency, and the term helmet fire is used jokingly to say that the pilot is undergoing so much stress that his brain is on fire or smoke is coming out of his ears.

Pilots most frequently get task-saturated when flying instrument approach

Instrument approach

For aircraft operating under instrument flight rules , an instrument approach or instrument approach procedure is a series of predetermined maneuvers for the orderly transfer of an aircraft under instrument flight conditions from the beginning of the initial approach to a landing, or to a point...

es, especially in actual instrument meteorological conditions

Instrument meteorological conditions

Instrument meteorological conditions is an aviation flight category that describes weather conditions that require pilots to fly primarily by reference to instruments, and therefore under Instrument Flight Rules , rather than by outside visual references under Visual Flight Rules . Typically, this...

. A complex procedure must be flown while making radio calls, changing the speed and configuration of the airplane, and maintaining assigned altitudes, all while flying by reference to instruments

Flight instruments

Flight instruments are the instruments in the cockpit of an aircraft that provide the pilot with information about the flight situation of that aircraft, such as height, speed and altitude...

. When the sum of these tasks exceeds the pilot's capability to deal with them effectively, he becomes task saturated and unable to perform any one of the tasks proficiently. The pilot may lose situational awareness, become confused, disoriented, may stammer on the radio, may forget how to fly the approach or what his last clearance was, and this can rapidly develop into an unsafe situation, in many cases leading to missed approach

Missed approach

Missed approach is an instrument flight rules procedure which is a standard component segment of an instrument approach. Generally, if the pilot flying or the pilot in command determines by the time the aircraft is at the decision height or missed approach point , that the runway or its...

, airspace violation, mid-air collision

Mid-air collision

A mid-air collision is an aviation accident in which two or more aircraft come into contact during flight. Owing to the relatively high velocities involved and any subsequent impact on the ground or sea, very severe damage or the total destruction of at least one of the aircraft involved usually...

, controlled flight into terrain

Controlled flight into terrain

Controlled flight into terrain describes an accident in which an airworthy aircraft, under pilot control, is unintentionally flown into the ground, a mountain, water, or an obstacle. The term was coined by engineers at Boeing in the late 1970s...

or any of a number of disasters.